1. Field of the Invention
The present invention relates to an imaging device, and more particularly to a technology for detecting an inclination of the imaging device.
2. Description of the Related Art
An imaging device operated by a user may capture an image of a target object (to be imaged) while the imaging device is undesirably inclined to the horizontal direction (or horizon) in a space or field of view to be imaged (such space or field of view being hereafter referred to as “image space”) when it is difficult for the user to find the horizontal direction in the image space, such as when capturing an image while the imaging device is directed above the horizon in the image space. In this case, it may become necessary to modify the captured image. Conventionally, such an image is modified by trimming, such that the image is rotated by a predetermined angle, and then a peripheral portion of the image is removed. However, a trimmed image has a problem in that the composition of the trimmed image may not be what the user intended, because a portion of the image is removed by the trimming.
Various imaging devices are known in the related art. For example, Japanese Laid-open Patent Publication 2003-263643 discloses an imaging device which analyzes a captured image of a target object to be imaged so as to calculate vanishing points of three point perspective, and uses the distribution of the vanishing points so as to determine an image capturing direction of the target object. However, this imaging device determines the image capturing direction of the captured image, i.e. after capturing the image. Thus, it is not possible to prevent the user from capturing a target object while the imaging device is inclined to the horizontal direction in an image space.
Similarly, Japanese Laid-open Patent Publications 2002-344723 and 2001-236509 disclose imaging devices which detect an inclination of a captured image in an object space after capturing the image so as to rotate or trim the image. Thus, these patent publications cannot solve the above-described problems, either. On the other hand, Japanese Laid-open Patent Publications 2006-324948, 2006-287768 and 2002-290818 disclose imaging devices each provided with an inclination detection sensor for detecting an inclination of the imaging device. However, due to the necessity of providing the inclination detection sensor, it is difficult to reduce the manufacturing cost of the imaging device.